Air-spring.



w. L. OSTENDORF.

AIR SPRING.

, EPPLIGATION IILED DEC. 21, 1912. 1,108,930; Patented Sept. 1,1914,

5 SHEETSSHEET 1. F70./. '11.

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ATTORNEY.

"WA BY I w. L. 'OSTENDORF;

AIR SPRING. APPLICATION FILED DBO. 21, 1912. I 1, 1 08,930. Patented Sept. 1, 1914.

' 5 SHEETSSHEET 2. [70.2.

r WITNESSES 7/ 3 I] 5 '7 29 INVENTOR.

2 By? ,a

W. L. OSTENDORR- AIR SPRING.

APPLICATION FILED DEG. m 1912.

Patented Sept. 1, 1914..

5 SHEETS-SHEET 5.

INVENTOR. W

ATTORNEY IZFW "pigessure of the air-spring to properly support shocks or abnormal reciprocation.

NIT D TAT S PATENT OFFICE.

WILHELM L. OSTENDORF, OF VIILKINS TOWNSHIP, ALLEGHENY COUNTY, PENNSYL- VANIA, ASSIGNOB- 0F ONE-THIRD T'O ALBERT H. KLESA AND ONE-THIRD TO FRANK P. SCOTT, OF ALLEGHENY COUNTY, IENNSYLVANIA.

AIR-SPRING.

Specification 0t Letters Patent.

Patented Sept. 1, 1914.

Application filed name; 21.1912. Serial No. 737,836.

Z '0 all whom it may concern: I

Be it known that I, WILHELM L. .OSTEN- noun, a citizen of the United States, and residing in the township of Wilkins, in the county of Allegheny and State of Pennsylvania, have invented or discovered new and useful Improvements in Air-Springs, of which the following is a specification.

My invention relates to shock-absorbers or cushion-devices intended for use as a substitute for or in combination with the usual resilient metal springs ofan automobile or other vehicle. g

It more particularly relates to the type of such devices wherein a compressible fluid agent and an incompressible fluid agent are used together, such, for instance, as both air and oil or some other liquid.

Generally speaking, my invention comprises novel means for regulating the internal and cushion the particular load to be carried. Means are provided for this purpose which are both adjustable and automatic. Means are also provided for throttling or retarding the reciprocation ot'the telescoping elements of the air-spring against sudden Means are also provided for the automatic lubrication of the sliding joints and packing of the device and also the trunnions or other elements whereby the air-spring is mounted on the vehicle.

Other novel and important features of construction and arrangement of parts will appear from the following description.

In the accompanying drawings, Figure 1 is an elevation of my invention which for convenience I herein term an air-spring; Fig.2 is a vertical section of the same along 'the line II-II in Fig. 1; Fig. 3 is a hori- "zontal section, turned 90 degrees-clockwise,

along the line IIIIII in Fig. 2; Fig. 4 is a, vertical section along the line IV lV in,

Fig. 3 and showing the piston valve con "netting therelief passages; Fig.6 is'a .s-imilar section along the line V-V in .Fig. 3;

F G is a horizontal section along the line VI,VI in Fig. 2;.Fig. 7 is a similar view along the line VII-VII in, Fig. 2; Fig. 8 is an elevation of the split-spring ring used to hold the. packing of the scraper snugly in contact with the cylinder; Fig. 9 isa plan view of the same Fig. 10 is a. plan view of the expander ring usedinconnection with the packing cups; Fig. 11 1s a side elevation of the same; F121. 12 1s a View slnnla-r to Fig.

5 showing a modification, and Fig. 13 is a view similar to Fig. 2 showing a modification.

The following is a detailed description of the drawings.

A s cylinder, shown as depending, re.-'

ciprocating between an outer or bearing tube .13 and aninner or piston tube C, between which lattertube and said cylinder is provided a packed sliding joint. Thefree 'or upper end of cylinder A is closed by a head which in Figs. 1 and 2 is composed of an an--' .nular body or ring member 1 threaded upon the end of cylinder A, and a domed cap 2 threadedon ring 1. The cap 2 is provided with a spring valve 3 through which air and liquid may be introduced into the interior of the air-spring tocharge the same and which is preferably closed by a suitable protective cap as shown. As a convenient means for mounting the cylinder 1 upon the frame or other-portion of a vehicle, I may provide a pair of oppositely placed trunnions or bearings fl integral with or mounted upon the ring 1 or cylinder A. The lower or outer end of bearing tube B is exteriorly threaded and provided with an internal an nular flange'o. p

D is a pan or fluid reservoir, preferably of larger diameter than tube B whose lower end is screwed into the threaded contracted top flange 6 of pan D.

7 is a port in the side of pan D for the introduction of liquid, such as oil, the level of oil being preferably that of the flange 5. S is a screw plug adapted to close said port 7. i The flange 6 is provided with a plurality of ports 9 communicating with the interior of the hollowlocknut 1O screwed on tube B 'tightly' down against the pan 1) as shown.

11, pref up into the nut 10 and any oil in said nut will flow down the inclined bafile into the pan' D.

The upper or open end of bearing tube B is threaded into a bearing ring E which has a sliding fit with the cylinder A. A stop ring 16 is threaded on the inner end of cylinder A to prevent said cylinder being drawn out of said bearing ring by an abnormal expansion of the air-spring. A cushion ring 17, preferably of compressible material, is secured in the end of tube B against the ring E to receive the impact of ring 16. A seat 18 in the inner wall of tube B supports ring 17 in place.

The boreof bearing E is provided with a circumferential groove 19 which encircles the cylinder A and collects excess lubricant.

' Said collected'lubricant is led through passages 20 downwardly inclined through the material of ring E'to the bearing surfaces of trunnions 21 integral with or mounted upon the ring E as a convenient means for mounting the bearing tube on the vehicle.

22 is an annular scraper snugly encircling the cylinder A and having a depending flange 23 which is secured to the top of bearing ring E as by screws 24:.

25 is an annular washer or packing, preferably of felt, within scraper 22 and held in closed contact with cylinder A by means of an encircling split-spring ring 26 provided with outwardly extending spring fingers 27 which bear against the inner wall of scraper 22, thus resiliently compressing the packing 25 against the wall of the cylinder. It is evident that said scraper will remove the dust, dirt or mud collecting on the exposed wall of cylinder A and together with ts packing 25 prevent such foreign material entering between said cylinder and the bearing ring E. i

The piston tube U has a sliding fit in cylinder A and its lower end is closed by screwing therein a head F. The head F seats upon the flange 5 of tube B and is kept from rising therefrom by the internal pressure of the air-spring.

28 is a compressible packing ring or spacer interposed between the head F and the tube B to maintain said tube laterally in its proper relation to said tube B but the comof an annular seat or recess 29 in the head F.

The details of construction of head F are hereinafter described in full.

G is a ring member screwed by means of its annular flange 30 into the upper end of the piston tube C. Said member Gr is composed of the depending flan e 30, the upwardly extending flange 31 o less dlameter and externally threaded, and a horizontal intermediate web 32 whose edge has a sliding lit with the cylinder A and which forms a seat for the leather packing cup 33, the outer edge of said seat being curved upwa-rdly as shown to support the angle of said cup 33. The cup is locked in place by means of a washer 34 and a nut 35 screwed down on annular flange 31 of member G.

36 represent spanner holes in nut 35.

y 37 isian annular cone expander Whose beveled edge bears against the reversely beveled top edge of cup 33 and forces the same into snug contact with the wall of cylinder A.

38 are upwardly extending spring-fingers partially cut from the top of expander '37 and compressed by the lower edge of the nut 39- screwed on the flange 31 of member G. A resilient outward pressure is thus exerted on the cup 33 which tightly and effectually packs the oint between the cylinder A and the piston tube 0. The nut 39 is of substantially inverted L-shape crosssection with an inwardly inclined top surface, as shown.

40 is an annular body of fibrous material or lubricator mounted as shown in the angle of nut 39 and resting upon the top of expander 37, said packing or lubricator being in light contact with the wall of cylinder A. The top surface of nut 39 is pro vided with a concentric annular groove of channel 41 from which vertical ports 42 lead at intervals to the lubricator 40.

Means, hereinafter described in full, deposit oil or other lubricating liquid upon the top surface of nut 39 which fills groove 41 and descends down through ports 42 to saturate the lubricator 40 which thus is enabled to properly lubricate the wall of cylinder A. The surplus liquid flows inwardly ofi' of the top of nut 39 down into the interior of the air-spring. A portion of the lubricant applied to cylinder A works down pressibility of said ring 28 enables the head i between said cylinder and,the piston tube,

lubricating stop ring 16 and Working up between the bearing tube B and cylinder A- -to lubricate the bearing ring E and collectmg in groove 19 thence passing to the trunnions 21. Lubricant also seeps or flows from the lubricator down between-the spring -fingers 38 of expander 37 into the annular space between the cup 33 andthe flange 31 of the member G thus maintaining in 0011 tact with said cup a suliicient body of liq uid to thoroughly lubricate the leather or other material of said cup. The surplus lubricant escapes from said annular space through the horizontal ports 43 into the bore of member G and then to the bottom of the air-spring.

i The head F containsa low-pressure pump which raises liquld or liquid and air from high-pressure pump raises liquid from the bottom of the air-spring proper to supply the lubricator 40 and it also serves to throttlethe reciprocation of the cvlinder A and the tubes B and'C, as is hereinafter described,

"The head 1*" is provided witha central vertical bore 44 enlarged circumferentially and closed at the bottom. The upper end of the bore 44 communicates at its top with an enlarged bore 45 which in turn'eommunb cates at its top with a-still larger bore 46 which is threaded. Screwed into the bore 46 is the lower end of high-pressure pumptube I-L-the lower end of said tube holding in place a perforated plate 47 which separates bores 45 and 46.

'48 is a plunger adapted to reciprocate in the bore 44' and having an enlarged or flanged head 49 .which reciprocates in the bore 45, its upward movement being limited by the plate 47. V v

A vertical bore 50 extends through the head F, its lower portion being contracted to form a seat for the upwardly opening ball-valve 51.' The upper portion of bore 50 is countersunk and threaded to acc'ommodate the seat '52 of the upwardly opening .bsllsvalve 53 held against displacement bya cross-pin 54. A lateral passage 55 leads from. the bore 50 intermediate of'the ballv-alves into the bottoinzof the bore 44. It is evident that when plunger 48 rises, through the influence of the high-pressure pump as will be described, the lower ball-valve 51 is opened and lubricant and air drawn from the pan D into the bottom of the bore 44. During-the descent of plunger 4.8 the ballvalve 51 is closed and ball-valve 53 opened, permitting the fluid drawn as above described from pan D to he forced up into the interior of the air-spring. To prevent the pumpingof liquid exclusively from pan D 71 is a passage in head and to enable thesaid low-pressure-pump to 4 draw sufficient air from said pan into the interior of .thc air-spring to compensate for any leakage to atmosphere as between the tubes vB and C and thecylinder A, I provide the lower end of the bore 50 with an intake'body or mixer 56 having a'vertical ,bore'57, a low level liquid passage 58 and an air-passage 59 whose intake is above the normal level of liquid in, pan D but whose outlet into bore 57 is at the level of passage 58. It is evidentthat a quantity of liquid would normally stand in the bottom of bore 57 which would ascend said bore first into' the bore 50 to be followed by mixed liquid and air; I prefer tomake the air-passage 9 of somewhat greater capacity than liq uid passage '58 to' facilitate the intake of the mingled fluids.

The high-pressure pump mechanism is as follows. 60 is a plunger rod mounted in any convenient manner to reciprocate with cylinder A and fitting loosely in the tube H. As a convenient method of mounting he rod 60, I have shown in Figs. 2 and 7 a metal diaphragm. orplate 61 held between the top of cylinder A and an internal -lip'on ring member 1. Plate 61 is provided with a diametric slotted opening 62. The

rod 60 is provided with a pair of adjacent cross-heads 63 separated for the thickness of'the plate 61 by a-small washer 64. The upper cross-'head-is of proper size to pass through the slot 62 when turned in the proper direction. In assembling, the crossheads are turned .to register with said slot and the upper cross-head is inserted through the latter. The'orossheads are now turned at right angles to said slot, having between them a portion of the plate 61. A cotter pin, or pins, is now inserted through registering, holes in said cross-heads and said plate to hold the plunger rod securely in its mounting, The lower-end of rod 60 is enlarged to form a head 66 having a sliding fit in the tube H. Said head is provided ient' means of rendering the. tension of the valve spring adjustable, so that the valve may be made to open at varying pressures, I prefer to form the seat thereof by screwing the nipple 7 O in the bore 67 the adjustment of said nipple regulating the strength of the valve-spring.

F connecting the bottom of bore 45 with an open channel 72 in said head, the upper end of said passage 71 being closed by the flanged top of plunger 48 when said plunger is depressed. 73 is an L'shape passage in the top of plunger 48 adapted to connect the passage 71 with the .of tube I-I above said head. As a convenbore 46 and the interior of tube H when said plunger is raised, as shown in Fig. 2, thus admitting liquid into said tube. 'llhus during the ascent of the head 66 in theitube H liquid is drawn into the tube H to the full capacity of spring of valve 68, openin the same and" permittmg liquid to pass t rough bore 67 and ports 69 into the tube l-I abov, the head 66 to be carried up by the reciprocation of the head 66 to overflow the top of tube H. As previously explained, a portion of said overflow is deposited upon the top of nut 39 to supply the lu'bricaton 40 and lubricate the cup leather, the remainder of-said overflow escaping down between the member G and the tube H, suliicient space between the same being provided for that purpose.

It is evident that the high-pressure pump,

in addition to its functions of operating the lmv-pressure pump and lubricating the sliding joints, also throttles or retards the reciprocation of the elements of the air-spring tor the reason thatv the relatively small capacity of passage 71 compared to the capacity of tube 1-): causes a deficiency in said tube of liquid beneath the head 66, and the low DEC-SSH beneath. said head retards or throttles its ascent and likewise throttles the ascent of the cy" 'dcr A. By regulating the capacity of said assage 71 in relation to that of the tube H I may vary the retarding effect to suit various conditions' The downstroke of cylinder A is retarded or throttled owing to the fact that the tension of the spring of valve 68 must be overcome before the liquid in the lower portion of tube H may escape up past the head 66. By adjusting the tension of said valve-spring, it may be arranged to open at any desired pressure, thus regulating sa d tln'ottling action. The throttling function of the llifllbPltSElllO pump is very important in counteracting Hll(l(ll:ll shocks and abnormal tendencies toward expansion or contraction of the airspring. The air-spring is thus rendered less sensitive and responsive.

. Another function in which the high-pressure pump participates isthc automatic relief of excessive pressure in the interior of the airspring. Such excessive pressure passage 71. The descent 0t head 66 in the tu e H, in unison with-the de-- scent of cylinder A, forces plunger &8 to

passage 71 and.

breather already described.

and eventually render it inoperative. The following is a description of this feature of my invention: 7%" is a port in the tube H below the normal limit of upstroke of head 66, and 75 is a tube connecting said .port with-a vertical bore in the head F ,w. 1086 lower end'ls closedby a screw-plug .77! The lower end of bore 76 is intersected by a horizontal passage 78 in head F which is acontinuation of the channel 72. is a piston valve sliding in boreflt"; and normally held up against the bottom of tube 75 by the coiled spring 80. A depending valve stem 80 guides the spring 80,

and limits the downward movement of the valve 79 by contacting with the plug 77.

.Valve 7 9 is provided *ith the circumferential groove 81 which, when said valve is depressed t6 its lowermost position establishes communication between two passages 82 and 83 formed in the head F.

would impair the eiiiciency of the air-spring The passage 82, Fig. 4, .is. L-shape and actuated valve 84 opening toward pan D...

The valve Set is adjustable to open at any desired pressure in passage 83.

' While the head 66 is descending in tube H above the port 74:, the pressure intube H, entering the tube 75 and bore 76, depresses piston-valve 79, until it establishes communication between passages 82' and '83 thus admitting air-spring pressure into pas sage 83 against spring-closed valve 84. In

case such pressure is suflicient to open, said valve against its spring,. said excess of pressure will be exhausted through passa'ges 82 and 83 into the pan D whence it will be dlssipated to atmosphere through the In case oil or' other liquid has accumulated above the level of the intake of passage 82, said excess oil will likewise be relieved intolpan D. Immediately upon the escape of such excess pressure fofair or liquid or both from the interior oflthe air-spring through said valve 84,5shid valve will hutomatically close and prevent further escape. Unless the pressure in the air-spring is gi ca tcithan that at which the valve 84 is set to'open, said valve will" remain closcdQ. Therefore the adjustment of valve Si controls the air-- spring pressure and by means] ofsuch adjustment the air-spring may be accurately,

set at any pressure which may be required to properly support and cushion any particular load. .As soon as the head GGpassos the port 74:, the actuating pressure is re lieved in bore 76 and the piston-valve 79 rises and shuts off communication between passages 82 and 83. The admission of airspring pressure through passage 78 under the piston-valve 79 balances the fluid pres *sure against both ends of said piston-valve preferably at a level with the upper end of Jassa e 82. The lower end of a ei e 85 a: a: b l

' 1s usually closed by a screw plug 86.

' the relief valve 84.

The air-spring is charged for service as follows plug '86 unscrewed from the lower end of gage pipe 85. Liquid, such as for instance, oil, is introduced into tube C through the top valve 3 until it overflows the top of gage pipe 85. WVhen the excess liquid has escaped the plug 86 is screwed home in pipe 85. adjusted to open when the pressure admitted to it through passages 82 and 83 rises above the point desired in the air sprung. The pan D is now screwed on and filled to the proper level. Air is now introduced through the top valve 3 until the pressure in the air-spring substantially equals that determined by the adjustment of The spring is now ready for use.

In operation the low'pressure pump will raise oil and air from the pan D to the interior of the air-spring and the high pres sure pump will raise oil from the bottom of tube 0 to the lubricator 40, permitting the excess to drop down again into the bot-- tom of tube C. The high pressure pump will retard and cushion the reciprocation of the telescopic elements and any undue rise in air pressure or of oil. in the air-spring will be automatically relieved into' pan D, whence the excess air pressure will escape through the breather to atmosphere.

In Fig. 12 I show a slight modification, providing vertical ports 87 through the flange 5 of the bearing tube B under the compressible packing 28. By this means any excess of oil gathering in the bottom of tube B outside of tube C may be allowed to seep down into pan D and excess air pressure in pan D may be relieved through the ports 87 and up between cylinder A and tube 13 to atmosphere. The ring 28 is in' this case preferably of fiber thus forming a filter for the oil descending through ports 87 t cleanse the same from dirt and grit.

The pan D is removed and the:

The automatic relief valve, 84; is nowaway with the ring member G and substituted therefor an annular offset 90 on the upper end of the piston tube G upon which are mounted the split-spring packing rings 91 spaced apart by spacers 92 and clamped in position by the lower horizontal flange of the nut 39, which in this case encompasses the lubricator 40 on three sides and which screws into the threaded end of the tube 0 as shown.

In Figs. 1 and '2 I have shown a domed cap 2 closing the upper end of cylinder A and I prefer this type as providing additional air pressure capacity, but I may substitute any other character of closure, such, for instance that shown in Fig. 13 wherein the top of said cylinder is flatand the rod 60 is attached directly thereto. This type is convenient where economy in space is necessary and the valve 3 may be placed at one side instead of on top. Here I have indicated'in dotted lines the trunnions 4 shifted longitudinally 90 giving additional elasticity to the air-spring mounting.

Although, for the sake of clearness, I have I the admission of liquid to said pump, the ca pacity of said valve being less than that of said pump whereby the reciprocation of said cylinders is throttled.

2. In an air-spring, telescoping cylinders forming a cushion chamber and containing fluid, a pump adapted to raise said fluid in said chamber and consisting of a pump barrel mounted in unison with one of said cylinders and a plunger mounted in' unison with the other cylinder and reciprocating in said barrel, and a resiliently'seated valve in said plunger whereby the reciprocation of said cylinders is throttled.

3. In an air-spring, telescoping cylinders forming a cushion chamber and containing fluid, a pump adapted to raise said fluid in said chamber and consisting of a pump barrel mounted in unison with one of said cylinders and a plunger mounted in unison with the other cyliuder,-, and a valve in said plunger of less capacity than said barrel whereby the reciprocation of said cylinders is throttled.

a. In an air-spring, telescoping cylinders forming a cushion chamber and containing fluid, a low pressure reservoir communicating with said chamber by means of a passage, means whereby said passage is blocked but when the pressure in said chamber rises above a predetermined degree said passage opens and permits the excess fluid to escape into said reservoir, and a pump actuated by the reciprocation of said cylinders adapted to transfer fluid from said reservoir to said chamber.

5. In an air-spring, telescoping cylinders forming a cushion chamber and containing fluid, a low pressure reservoir communicating with said chamber by means of a passage, a relief valve in said passage whereby excess pressure in said chamber may be relieved into said reservoir, and means operated by the reciprocation of said Lylinders' for admitting chamber )ressure during the expansion of said te escoping cylinders through said passage to said relief valve.

6. In an air-spring, telescoping cylinders forming a cushion chamber and containing fluid, a reservoir communicating with said chamber by means of a passage, a relief valve in said passage whereby excess pressure in said chamber maybe relieved into said reservoir, and a piston valve intersecting said passage and actuated by the reciprocation of said cylinders whereby said passage is alternately opened and closed.

In an air-spring, telescoping cylinders forming a cushion chamber and containing fluid, a pump actuated by the reciprocation of said cylinders, a reservoir communicating with'said chamber by means. of a passage, a relief valve in said passage, and means controlled by said pump for admitting chamber pressure at intervals through said passage to said relief Valve.

8. In an air'spring, telescoping cylinders forming a cushion chamber and containing fluid, a pump barrel mounted on one of said cylinders, a pump plunger mounted on the other cylinder and reciprocating in said barrel, a reservoir communicating with said chamber by means of a'passage, a relief valve in said passage whereby excess pressure in said chamber may be relieved into said reservoir, a piston valve intersecting said passage and adapted to closethe same, and means whereby the movement of said plunger in said barrel actuates said piston valve and opens said passage at intervals to admit chamber pressure to said relief valve.

9. In. an air-spring, telescoping cylinders forming a cushion chamber and containing fluid, alow pressure, reservoir c0mmunicating with said chamber by means of a passage, an automatic relief valve in said passage whereby excess fluid in said chamber is relieved into said reservoir, automatic means for maintaining a lower pressure in said reservoir than in said chamber, and a pump actuated by the reciprocation of said cylinders for transferring fluid from said reservoir to said chamber.

10. In an air-spring, telescoping cylinders forming a cushion chamber and containing fluid, a low pressure reservoir communicating with said chamber by means of a passage, an adjustable automatic relief valve in said passage whereby excess fluid in said chamber is relieved into said reservoir, automatic means for maintaining a lower pressure in'sa-id reservoir than in said chamber,

and a pump actuated by the reciprocation ofsaid cylinders for transferring fluid from said reservoir to said chamber.

11. In an air-spring, telescoping cylinders forming a cushion chamber, a reservoir, means for relieving excess fluid from said chamber to said reservoir, and a breather connecting said reservoir to atmosphere.

12. In an air-spring, telescoping cylinders forming a cushion chamber, a reservoir, means for supplying fluid from said reservoir to said chamber, means for relieving excess fluid from said chamber to said reservoir, and a breather connecting said reservoir to atmosphere 13. In an air-spring, telescoping cylind rs forming a cushion chamber, a reservolr con taining a liquid and a gasecusfluid, means for feeding said fluids from said reseryeir to said chamber, and -fluid mixing means associated with said. feeding means.

1.4. In an air-spring, telescoping cylinders forming a compression chamber, a reservoir containing a liquid and a gaseous fluid, a pump feeding fluid into said chamber, and means whereby said pump injects both of said fluids into said chamber.

15. In an air-spring, telescoping cylinders forming a compression chamber, a reservoir containing a liquid and a gaseous fluid, a pump feeding fluid to said chamber, and a combined liquid and gaseous intake for said pump.

16. In an air-spring, telescoping cylinders forming a cushion chamber and containing liquid, a packed sliding joint for said cylinders, a lubricator mounted on one of said cylinders and contacting with the wall of the other cylinder, and a pump operated by the reciprocation of said cylinders raising said, liquid in said chamber and discharging the sa'meupon said lubricator.

17. In an air-spring, telescoping cylinders forming a cushion chamber and containing liquid, a packed sliding, joint for said cylinders, a'lubricator mounted on one of said cylinders and contacting with the Wall of the other cylind'ei, a feeding device superimposed on said lubricator, and a pump oper- ,a packed sliding joint between said cylinbearing tube, and a piston tube mounted in .in the other cylinder, a pump plunger recipated by the reciprocation of said cylinders raising said liquid and discharging the same upon said feeding device.

18. In an air-spring, telescoping cylinders forming a cushion chamber and containing-- liquid, a packed sliding oint for said cylinders, a lubricator mounted on one of said cylinders and contacting with the wall of the other cylinder, a feeder adapted to contain liquid superimposed on said lubricator and having ports communicating with the latter, and a pump operated by the reciprocation of said cylinders raising said liquid and discharging the same upon said feeder.

19. In an air-spring, telescoping cylinders forming a cushion chamber containing fluid, a packed sliding joint between said cylinders, a pump tube mounted on one of said cylinders and having an intake in the bottom of said chamber, a diaphragm mounted in the other cylinder, and a pump plunger mounted 'on said diaphragm and reciprocating in said tube.

20. In an air-spring, telescoping cylinders forming a cushion chamber containing fluid,

ders, a pump tube mounted on one of said cylinders and having an intake 1n the bottom of said chamber, a diaphragm mounted rocating in said tube, and cross-heads on said plunger embracing between them said diaphragm.

21. In an air-spring, telescoping cylinders forming a cushion chamber containing fluid, a packed sliding joint between said cylinders, a pump tube mounted on one of said cylinders and having an intake in the bottom of said chamber, a diaphragm mounted in .the other cylinder and provided with a diametric slot, a plunger rod reciprocating in said tube and provided with a pair of cross-heads, one of said cross-heads being adapted to be passed through said slot and to be turned out of registration therewith whereby said diaphragm is embraced between said cross-heads, and means for holding, said cross-heads against displacement.

' 22. In an air-spring, the combination of a bearing tube, a cylinder telescoping in said said bearing tube and telescoping in said cylinder, said piston tube being loosely mounted in said bearing tube and capable of movement in relation thereto, and a packed sliding joint between said cylinder and said piston tube.

23. In an air-spring, the combination of a bearing tube, a piston tube mounted in said bearing tube but unattached thereto so as to be capable of movement in relation to said bearing tube, a cylinder telescoping between said tubes, and a packed sliding joint between said cylinder and said piston tube.

24. In an air-spring, the combination of a bearing tube, a piston tube mounted in said bearing tube but unattached thereto so as to be capable of movement in relation to said bearin tube, a compressible spacer between said tu es, and a cylinder telescoping between said tubesfmd a packed sliding joint between said cylinder and said piston tube.

25. In an air-spring, a bearing tube, a cylinder telescoping in said bearing tube, a piston tube" supported insaid bearing tube and telescoping in said cylinder, means for lubricating the contacting walls of said tubes and said cylinder, and trunnions on said bearing tube provided with passages communicating with the interior of said bearing tube whereby lubricant'is supplied to said trunnions.

26. In an air-spring, a bearing tube, acylinder telescoping therein, a piston tube supported in said bearing .tube and having a packed sliding joint with said cylinder, and

a reservoir beneath said bearing tube communicating with the same for the downward passage of liquid from said bearing tube into said reservoir.

27. In an air-spring, abearing tube, a cylinder telescoping therein, a piston tube supported in said bearing tube and having a packed sliding joint with said cylinder, areservoir beneath said bearing tube and a filter interposed between said bearing tube and said reservoir whereby liquid escaping from said bearing tube into said reservoir is cleansed of impurities.

28. In an air-spring, a bearing tube having a closed lower end, a depending cylinder telescoping therein, a piston tube seated in -said bearing tube and telescoping in said cylinder, a packed sliding joint between said cylinder and said piston tube, means for supplying a lubricant to said joint, and a filter in the lower portion of said bearing tube whereby excess liquid escaping into the bottom of said bearing tube is cleansed in its passage.

29. In an air-spring, telescoping cylinders having a packed sliding joint and forming a compression chamber, a high pressure pump. adapted to raise a. liquid within said chamber, a reservoir, and a low pressure pump adapted to raise a liquid from said reservoir and discharge the same to lubricate said packed join.

30. In an air-spring, telescoping cylinders forming a cushion chamber and containing fluid, a pump actuated by the reciprocation of said cylinders, a reservoir communicating with said chamber by means of a passage, a relief valve in said passage, a second pump adapted to transfer fluid from said reservoir to said chamber, and means controlled by said first pump for admitting chamber pressure at intervals through saidpassage to saidrelief valve. j

31. In an air-spring, telescoping cylinders forming a cushion chamber and containing fluid, said chamber being provided with an chamber, a pressure relief valve in said passage whereby excess pressure may be relieved from said chamber, a piston valve intersecting said passage and adapted to close the same, and means whereby the movement of said plunger in said barrel actuates said piston valve and opens said passage at intervals to admit chamberv pressure to said relief valve.

33. In anair-spring, telescoping cylinders forming a cushion chamber and containing fluid and having "a passage leading therefrom for the escape of excess pressure, an

set

automatic relief valve in said passage, a

,pumpoperated by the reciprocation of said cylinders, and means controlled oy pump pressure for-intermittently admitting cham- 1w pressure through said passage to said valve.

34. In an air-spring, telescoping cylinders forming a cushion chamber and containing fluid,'a pump actuated by the reciprocation of said cylinders, asecond pump supplying. fluid tosaid chamber and actuated by said first pump, and a valve controlling the admission of fluid into said-first pump from said chamber,

35. In an air-spring, telescoping cylinders forming a cushion chamber and containing fluid,v a pump actuated by the reciprocation of said cylinders, a second pump actuated by said first pump for supplying fluid to said chamber, and i valve intermediate of said-pumps contr ting the introduction of fluid from said el'iamber to said first pump.

36. In an air-spring, telescoping cylinders forming a cushion chamber and containing fluid, a fluid reservoir, a pump actuated by the reciprocation of said cylinders adapted to raise the fluid Within said chamber, a second pump actuated by said first pump adapted to supply fluid from said reservoir to said chamber, and a valve intermediate of said pump controlling the admission of fluid into said first pump from said chamber.

37. In an air-spring, telescoping cylinders forming a cushion chamber and containing fluid, a fluid reservoir beneath said chamber, a pump actuated by the reciprocation of said cylinders adapted to raise fluid within said chamber, a second pump actuated by said first pump adapted to raise fluid from said reservoir to said chamber, and a valve intermediate of said pumps controlling the admission of fluid from said chamber into said first pump.

88. In an air-spring, telescoping cylinders forming a cushion chamber and containing a fluid, a low pressure reservoir beneath said chamber, means for filling said reservoir, a pump actuated by the reciprocation of said cylinders adapted to raise fluid within said chamber, a second pump actuatedby said first pump for supply fluid from said reservoir to said chamber, and a valve intermission of fluid from said chamber intofsaid first pump.

39. In anair-sprlng, telescoping cylinders forming a cushion chamber and having a v0nd pump actuated by said first pump and adapted to supply" fluid from said reservoir to said chamber.

Signed at Pittsburgh, Penna. this 17th day of December, 1912.

WILHELM L. OSTENDORF, Witnesses E. A. LAWRENCE, J. H. HARRISON.

Copies of this may be obtained for fivecents each, by addressing the "Commissioner of Patents,

Washington, D. G.

so mediate of said pumps controlling thead 

